Despite being very flower-like. sea anemones are animals. When exposed on a shore or after disturbance, with a few exceptions, the tentacles are retracted and the anemone becomes an unattractive shapeless lump of tissue. A few species are unable to retract but can shed tentacles quite readily when attacked. When expanded as these photographs show, many can be strikingly coloured and beautiful.
All are carnivorous and use their tentacles to trap food which they transfer to the central mouth. Some types with fine, delicate tentacles take plankton but other big species are able to take quite large prey by dragging it down towards the mouth and expanding the body up and around the tentacles and prey and completely enveloping it. The anemone may then stay in this retracted state whilst digestion takes place.
Unlike on land, there are great colour variations between animals of the same species. It is common to find whilst diving a clump of Dahlia Anemones for instance, where one may be red and yellow with its neighbours being combinations of white, blue, purple, yellow, red and all shades in between - and all with different patterns.